From: Zoran Zaric Date: Mon, 7 Dec 2020 19:00:15 +0000 (+0000) Subject: Simplify dwarf_expr_context class interface X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e6bada58ebb64f9356e8912f921f30715b6c7308;p=thirdparty%2Fbinutils-gdb.git Simplify dwarf_expr_context class interface Idea of this patch is to get a clean and simple public interface for the dwarf_expr_context class, looking like: - constructor, - destructor, - push_address method and - eval_exp method. Where constructor should only ever require a target architecture information. This information is held in per object file (dwarf2_per_objfile) structure, so it makes sense to keep that structure as a constructor argument. It also makes sense to get the address size from that structure, but unfortunately that interface doesn't exist at the moment, so the dwarf_expr_context class user needs to provide that information. The push_address method is used to push a CORE_ADDR as a value on top of the DWARF stack before the evaluation. This method can be later changed to push any struct value object on the stack. The eval_exp method is the method that evaluates a DWARF expression and provides the evaluation result, in a form of a single struct value object that describes a location. To do this, the method requires a context of the evaluation, as well as expected result type information. If the type information is not provided, the DWARF generic type will be used instead. gdb/ChangeLog: * dwarf2/expr.c (dwarf_expr_context::dwarf_expr_context): Add address size argument. (dwarf_expr_context::read_mem): Change to use property_addr_info structure. (dwarf_expr_context::eval_exp): New function. (dwarf_expr_context::execute_stack_op): Change to use property_addr_info structure. * dwarf2/expr.h (struct dwarf_expr_context): New eval_exp declaration. Change eval and fetch_result method to private. * dwarf2/frame.c (execute_stack_op): Change to call eval_exp method. * dwarf2/loc.c (dwarf2_evaluate_loc_desc_full): Change to call eval_exp method. (dwarf2_locexpr_baton_eval): Change to call eval_exp method. Change-Id: I8abd0dbf93e74a8a5adce143bfdea83c802233c3 --- diff --git a/gdb/dwarf2/expr.c b/gdb/dwarf2/expr.c index 7f8e8134a4f..5e99a98e1e3 100644 --- a/gdb/dwarf2/expr.c +++ b/gdb/dwarf2/expr.c @@ -693,9 +693,10 @@ dwarf_expr_context::address_type () const /* Create a new context for the expression evaluator. */ -dwarf_expr_context::dwarf_expr_context (dwarf2_per_objfile *per_objfile) -: gdbarch (NULL), - addr_size (0), +dwarf_expr_context::dwarf_expr_context (dwarf2_per_objfile *per_objfile, + int addr_size) +: gdbarch (per_objfile->objfile->arch ()), + addr_size (addr_size), ref_addr_size (0), recursion_depth (0), max_recursion_depth (0x100), @@ -706,7 +707,7 @@ dwarf_expr_context::dwarf_expr_context (dwarf2_per_objfile *per_objfile) per_objfile (per_objfile), frame (nullptr), per_cu (nullptr), - obj_address (0) + addr_info (nullptr) { } @@ -831,13 +832,17 @@ dwarf_expr_context::read_mem (gdb_byte *buf, CORE_ADDR addr, return; /* Prefer the passed-in memory, if it exists. */ - CORE_ADDR offset = addr - obj_address; + if (addr_info != nullptr) + { + CORE_ADDR offset = addr - addr_info->addr; - if (offset < data_view.size () && offset + length <= data_view.size ()) + if (offset < addr_info->valaddr.size () + && offset + length <= addr_info->valaddr.size ()) { - memcpy (buf, data_view.data (), length); + memcpy (buf, addr_info->valaddr.data (), length); return; } + } read_memory (addr, buf, length); } @@ -880,8 +885,8 @@ dwarf_expr_context::push_dwarf_reg_entry_value caller_frame); scoped_restore save_per_cu = make_scoped_restore (&this->per_cu, caller_per_cu); - scoped_restore save_obj_addr = make_scoped_restore (&this->obj_address, - (CORE_ADDR) 0); + scoped_restore save_addr_info = make_scoped_restore (&this->addr_info, + nullptr); scoped_restore save_per_objfile = make_scoped_restore (&this->per_objfile, caller_per_objfile); @@ -1049,6 +1054,28 @@ dwarf_expr_context::fetch_result (struct type *type, return retval; } +/* See expr.h. */ + +struct value * +dwarf_expr_context::eval_exp (const gdb_byte *addr, size_t len, + struct dwarf2_per_cu_data *per_cu, + struct frame_info *frame, + const struct property_addr_info *addr_info, + struct type *type, + struct type *subobj_type, + LONGEST subobj_offset) +{ + this->per_cu = per_cu; + this->frame = frame; + this->addr_info = addr_info; + + if (per_cu != nullptr) + this->ref_addr_size = per_cu->ref_addr_size (); + + eval (addr, len); + return fetch_result (type, subobj_type, subobj_offset); +} + /* Require that TYPE be an integral type; throw an exception if not. */ static void @@ -2319,11 +2346,11 @@ dwarf_expr_context::execute_stack_op (const gdb_byte *op_ptr, case DW_OP_push_object_address: /* Return the address of the object we are currently observing. */ - if (this->data_view.data () == nullptr - && this->obj_address == 0) + if (addr_info == nullptr) error (_("Location address is not set.")); - result_val = value_from_ulongest (address_type, this->obj_address); + result_val + = value_from_ulongest (address_type, this->addr_info->addr); break; default: diff --git a/gdb/dwarf2/expr.h b/gdb/dwarf2/expr.h index b7605ffd28c..69a043da50e 100644 --- a/gdb/dwarf2/expr.h +++ b/gdb/dwarf2/expr.h @@ -119,19 +119,30 @@ struct dwarf_stack_value its current state and its callbacks. */ struct dwarf_expr_context { - dwarf_expr_context (dwarf2_per_objfile *per_objfile); + /* We should ever only pass in the PER_OBJFILE, while the ADDR_SIZE + information should be retrievable from there. The PER_OBJFILE + contains a pointer to the PER_BFD information anyway and the + address size information must be the same for the whole BFD. */ + dwarf_expr_context (struct dwarf2_per_objfile *per_objfile, + int addr_size); virtual ~dwarf_expr_context () = default; void push_address (CORE_ADDR value, bool in_stack_memory); - void eval (const gdb_byte *addr, size_t len); - /* Fetch the result of the expression evaluation in a form of - a struct value, where TYPE, SUBOBJ_TYPE and SUBOBJ_OFFSET - describe the source level representation of that result. */ - struct value *fetch_result (struct type *type = nullptr, - struct type *subobj_type = nullptr, - LONGEST subobj_offset = 0); + /* Evaluate the expression at ADDR (LEN bytes long) in a given PER_CU + FRAME context. Where TYPE, SUBOBJ_TYPE and SUBOBJ_OFFSET describe + expected struct value representation of the evaluation result. + The ADDR_INFO property can be specified to override the range of + memory addresses with the passed in buffer. */ + struct value *eval_exp (const gdb_byte *addr, size_t len, + struct dwarf2_per_cu_data *per_cu, + struct frame_info *frame, + const struct property_addr_info *addr_info = nullptr, + struct type *type = nullptr, + struct type *subobj_type = nullptr, + LONGEST subobj_offset = 0); +private: /* The stack of values. */ std::vector stack; @@ -196,14 +207,10 @@ struct dwarf_expr_context /* Compilation unit used for the evaluation. */ struct dwarf2_per_cu_data *per_cu; - /* Object address used for the evaluation. */ - CORE_ADDR obj_address; - - /* The data that was passed in. */ - gdb::array_view data_view; - -private: + /* Property address info used for the evaluation. */ + const struct property_addr_info *addr_info; + void eval (const gdb_byte *addr, size_t len); struct type *address_type () const; void push (struct value *value, bool in_stack_memory); bool stack_empty_p () const; @@ -214,6 +221,13 @@ private: CORE_ADDR fetch_address (int n); bool fetch_in_stack_memory (int n); + /* Fetch the result of the expression evaluation in a form of + a struct value, where TYPE, SUBOBJ_TYPE and SUBOBJ_OFFSET + describe the source level representation of that result. */ + struct value *fetch_result (struct type *type, + struct type *subobj_type, + LONGEST subobj_offset); + /* Return the location expression for the frame base attribute, in START and LENGTH. The result must be live until the current expression evaluation is complete. */ diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c index 039990dea34..228c48f3877 100644 --- a/gdb/dwarf2/frame.c +++ b/gdb/dwarf2/frame.c @@ -228,26 +228,16 @@ execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size, struct frame_info *this_frame, CORE_ADDR initial, int initial_in_stack_memory, dwarf2_per_objfile *per_objfile) { - dwarf_expr_context ctx (per_objfile); + dwarf_expr_context ctx (per_objfile, addr_size); scoped_value_mark free_values; - ctx.frame = this_frame; - ctx.gdbarch = get_frame_arch (this_frame); - ctx.addr_size = addr_size; - ctx.ref_addr_size = -1; - ctx.push_address (initial, initial_in_stack_memory); - ctx.eval (exp, len); - - CORE_ADDR result; - struct value *result_val = ctx.fetch_result (); + struct value *result_val = ctx.eval_exp (exp, len, nullptr, this_frame); if (VALUE_LVAL (result_val) == lval_memory) - result = value_address (result_val); + return value_address (result_val); else - result = value_as_address (result_val); - - return result; + return value_as_address (result_val); } diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c index 90ab2077c6d..fdf83859336 100644 --- a/gdb/dwarf2/loc.c +++ b/gdb/dwarf2/loc.c @@ -1430,8 +1430,6 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame, struct type *subobj_type, LONGEST subobj_byte_offset) { - struct value *retval; - if (subobj_type == NULL) { subobj_type = type; @@ -1443,22 +1441,15 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame, if (size == 0) return allocate_optimized_out_value (subobj_type); - dwarf_expr_context ctx (per_objfile); - ctx.frame = frame; - ctx.per_cu = per_cu; - ctx.obj_address = 0; + dwarf_expr_context ctx (per_objfile, per_cu->addr_size ()); + struct value *retval; scoped_value_mark free_values; - ctx.gdbarch = per_objfile->objfile->arch (); - ctx.addr_size = per_cu->addr_size (); - ctx.ref_addr_size = per_cu->ref_addr_size (); - try { - ctx.eval (data, size); - retval = ctx.fetch_result (type, subobj_type, - subobj_byte_offset); + retval = ctx.eval_exp (data, size, per_cu, frame, nullptr, type, + subobj_type, subobj_byte_offset); } catch (const gdb_exception_error &ex) { @@ -1528,30 +1519,24 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton, return 0; dwarf2_per_objfile *per_objfile = dlbaton->per_objfile; - dwarf_expr_context ctx (per_objfile); + struct dwarf2_per_cu_data *per_cu = dlbaton->per_cu; + dwarf_expr_context ctx (per_objfile, per_cu->addr_size ()); struct value *result; scoped_value_mark free_values; - ctx.frame = frame; - ctx.per_cu = dlbaton->per_cu; - if (addr_stack != nullptr) + if (push_initial_value) { - ctx.obj_address = addr_stack->addr; - ctx.data_view = addr_stack->valaddr; + if (addr_stack != nullptr) + ctx.push_address (addr_stack->addr, false); + else + ctx.push_address (0, false); } - ctx.gdbarch = per_objfile->objfile->arch (); - ctx.addr_size = dlbaton->per_cu->addr_size (); - ctx.ref_addr_size = dlbaton->per_cu->ref_addr_size (); - - if (push_initial_value) - ctx.push_address (ctx.obj_address, false); - try { - ctx.eval (dlbaton->data, dlbaton->size); - result = ctx.fetch_result (); + result = ctx.eval_exp (dlbaton->data, dlbaton->size, + per_cu, frame, addr_stack); } catch (const gdb_exception_error &ex) {